Monday, March 11, 2013

San Onofre: Closer to the Truth, Further from the Bluster


This sounds serious:
[Sen. Barbara] Boxer (D-Calif.) said in a letter to Nuclear Regulatory Commission Chair Allison Macfarlane that a confidential report obtained by her office shows Southern California Edison and Mitsubishi Heavy Industries, the Japan-based company that built the generators, were aware of design problems before the equipment was installed.

Boxer, who chairs the Senate Environment and Public Works Committee, said the report written by Mitsubishi raises concerns that Edison and its contractor rejected safety modifications and sidestepped a more rigorous safety review.
A little mysterious, yes? This is about San Onofre, which has been off-line for a little over a year because of a steam generator problem. If Edison and Mitsubishi pressed ahead with a problematic steam generator, that would be very bad, but also rather inexplicable.

Just to get you up to date, here’s a refresher course on what happened at San Onofre:
Both of San Onofre's reactors have been offline for more than a year. The Unit 2 reactor had been taken down for routine maintenance early in January 2012, but on Jan. 31, 2012, a small leak of radioactive gas prompted the shutdown of Unit 3.
Inspections revealed unexpected wear among thousands of metal tubes that carry radioactive water inside the plant's four steam generators, two for each reactor.
Our friend Rod Adams over at Atomic Insights explains why the idea of a conspiracy is highly unlikely:
Aside from the fact that such an assertion was absurd – why on earth would any corporation take the risk of installing components known to be faulty into a vital, multi-billion dollar production facility capable of producing between $1-$10 million in daily revenue – it exposed a visceral dislike [by Rep. Boxer] of a power source that has been cleanly and safely supplying 20% of the electricity in the United States for several decades.
Let’s call that last bit an opinion – Sen. Boxer generally nuclear energy a fair shake in her committee, though she can be pretty tough. Let’s call that an opinion, too.

Rod also clarifies what the Mitsubishi report says:
After many months of investigation, tens of thousands of hours of analysis, and hundreds of millions of dollars worth of lost production time, it is now clear that the two steam generators installed in San Onofre Unit 3 contained a minor manufacturing feature that resulted in a “perfect pitch” harmonic. At just the wrong condition – 100% steam flow – a combination of relatively dry steam, precisely manufactured anti-vibration bars (AVB), and densely packed u-tubes resulted in a few hundred (out of nearly 10,000) tubes vibrating with a large enough amplitude to make contact. The unexpected vibration and contact resulted in accelerated wear and caused one tube to fail while the steam generator was operating.
That sounds a lot more plausible and certainly not an effort by Mitsubishi and Edison to shoot themselves in the proverbial foot – well, head really, as such a conspiracy would certainly do considerable damage to both companies. The entire Mitsubishi report can be found here.

Now, the report can make your head spin – it’s very dense and detailed. The estimable Will Davis over at Atomic Power Review takes a crack at it:
The root cause of this problem is essentially not a design flaw per se, nor even a miscalculation.  It is the basic, fundamental belief that in-plane fluid elastic instability in a vertical U-tube steam generator is not possible if out-of-plane instability has been guarded against.  This principle is described several times in the linked MHI material.
Well, I told you it was head spinning – and this is the simplified version. A little more:
What this means is that the designers of steam generators have essentially used a Maginot Line principle in preventing out-of-plane fluid elastic instability... which was supposed to inherently then preclude any chance of in-plane fluid elastic instability, which leads to serious tube-to-tube wear.  Singularly focused effort to prevent out-of-plane FEI has led to the situation in which in-plane FEI did actually occur through a set of very complicated circumstances which, when investigated, eventually implicates practices of manufacturing tolerances, fitting, calculation and even design variance between the two units' steam generators.
I’d probably avoid the word “implicates” as it often appears with the word “criminally,” but that’s not what Will means here. These are, rather, the elements that have to be looked at to understand how the problem occurred. This is a hard post to excerpt – you should read the whole thing. Here, for me, is the bottom line:
Now we can see clearly that MHI [Mitsubishi Heavy Industries] felt that it had developed replacement steam generators for San Onofre which were world-class in their design prevention of tube vibration, based on all the years of experience MHI has had in fabricating steam generators for PWR-type nuclear power plants.
This is completely believable. As Rod points out, the nuclear energy industry has a “squeaky clean” profile for manufacturing QA. It’s an industry that avoids – has to avoid - low-quality junk. N-stamps that validate nuclear equipment, a highly capable (and always present) regulator, a very strong safety culture – all these and more keep the vigilance against shoddiness very high. And Mitsubishi isn’t exactly Moe’s Steam Generators out in the valley, running a two-for-one sale.

I’m sure there will be more to say about San Onofre. But the public release of the Mitsubishi report takes a lot of the edge off the harsher statements made by a few politicians about the facility.
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Speaking of which, both Rod and Will are really furious at the politics around this and particularly about statements made by Sen. Boxer and Rep. Edward Markey (D-Mass.) over the last month. Both Boxer and Markey pulled unflattering bits out of the Mitsubishi report to highlight, but the report makes that possible for them. There are unflattering bits in there.

In my view, a report by the maker of flawed equipment would be inherently suspect, but this episode – and perhaps bluster from Capitol Hill - has put Mitsubishi’s reputation on the line. Consequently, Mitsubishi has produced what seems to me an honest assessment, with a lot of detail to back it up.

So why did some of the comments from Congress seem so intemperate? I don’t know. I do know that the motives of politicians, especially the experienced ones, are rarely singular.

6 comments:

jimwg said...

I'm REALLY surprised how 104 nuclear plants by their independent initiative apart parent companies and on own common self-interest didn't circle wagons around SONGS and call on cool heads till the evaluations came out while citing nuclear's near nil mortality/damage record. Relatives tell me SONGS cover-up conspiracy theories of nuclear energy's "naturally inherent flaws" are running rampant out there, and coyly anti-nuclear Boxer's lack of calling off the dogs hasn't helped matters either.

James Greenidge
Queens NY

Anonymous said...

@jimwg
California likely has more anti-nuclear people than any other state in the nation. For these sort of people the facts only play a secondary role in determining their views and therefore it wouldn't really make much difference what any sort of independent review said because they will believe what they want to believe.

Your point about nuclear coverups and conspiracies leads me to a point I always find ironic. When there are problems at a nuclear plant they are always self reported or reported by the NRC and yet people are always claiming these are the result of coverups. If it were true that the industry and NRC were trying to cover things up then people would never hear about problems at nuclear plants but instead they get to hear about every single minor incident because they are all posted on the NRC website.

It reminds me of a situation we had at WBN2 where two contract employees were convicted of felonies for lying about work they had done. Anti-nukes claimed this showed how flawed nuclear quality assurance is and that problems are covered up but it seems that exactly the opposite was the case. A worker and his boss both lied and yet the problem was still discovered because there are so many additional quality checks like QA, QC, the NRC and the TVA OIG that no safety related work can get done without being inspected, reviewed or audited by multiple independant people. The two employees were a couple of bad apples out of a work force of 3000 and the other 2998 people were doing their job right and took them to task. Also, TVA did their job and reported the offenders to the FBI and they were convicted in federal court of forging the reports. So far as I can tell that is an example of everything working as it should to identify and resolve a problem and yet you can read dozens of anti-nuke horror stories about how this is proof that the system is flawed.

Lewis Conner said...

How do I contact the editor (if there is one) of NEI Nuclear Notes? Sorry to use this forum but I did not see any contact info on the main blog page. Thx.

Anonymous said...

Anti-nuke kooks have always been duplicitous SOBs when it comes to the industry's efforts to achive high levels of QA, security, and waste management. They clamor about "security", yet when information is made public, they use that to hammer the industry about it's supposedly lax attitude towards safeguarding secure information. They whine about "waste" being stored at plants, then yell about how "dangerous" it is to transport "waste', and so must oppose a central repository. When confronted with the question of where to store the used fuel, they say "at the plant sites". Then they turn around and complain about all this "nasty stuff" laying around plant sites, making for so-called "targets" of imagined terrorist attacks. It's a lose-lose proposition dealing with these bums.

Anonymous said...

Yeah, it's almost like they believe the plants shouldn't be operated at all.

Anonymous said...

Yes, they control the narrative to the point where that is the only possible conclusion. So that simply points out the dishonesty of those who say they are trying to find "solutions" or want "honest debate". They don't.